Diarrhoea and Oral Rehydration Therapy

Diarrhoea or acute gastroenteritis is a universal problem. The most frequent cause of acute gastroenteritis is an infection of the intestines. Such an infection results in an outpouring of fluid and electrolytes (sodium, potassium, chloride and bicarbonate) from the intestinal epithelial cells into the intestinal lumen, which is then purged out as diarrhoeal stool. Diarrhoea has been defined as passing of three or more loose or watery stools in a day. If there is vomiting along with loose stools; loss of large amount of body water and salts is imminent and would lead to dehydration. Infants and young children develop dehydration faster than adults especially in hot climates, when diarrhoea is also associated with fever. So the most significant harmful effect of diarrhoea is major loss of fluid and electrolytes. However during the infective diarrhoea the intestinal ability to absorb of glucose, salts, water and nutrients remain well preserved. Since the absorptive ability of intestines is not altered by diarrhoea, so the management of diarrhoea or acute gastroenteritis is possible with oral rehydration therapy (ORT).

For ORT, a standard solution of oral rehydration salts (ORS) prepared under the recommendations of World Health Organization (WHO) is administered through mouth in small amounts (50 to 100 ml) depending on the age of patient at regular intervals of time. For preparing a standard solution of ORS, the powder is dissolved in known quantity of boiled cooled or purified drinking water as mentioned on the packet of ORS. With oral rehydration therapy the death rate of people dying of severe dehydration due to diarrhoea has significantly come down and the requirement of intravenous drips has become almost negligible.

A packet of ORS contains 27.5 grams of essential salts to be dissolved in a litre of boiled cooled or purified drinking water. An ORS packet contains 20 grams of glucose, 3.5 grams of sodium chloride (common salt or table salt), 2.5 grams of sodium bicarbonate (backing soda) and 1.5 grams of potassium chloride. Packets of ORS are supplied free of cost at Primary Health Centers and Government Hospitals and dispensaries. Low salt content home-made fluids are equally good in emergency if a packet of ORS is not available immediately. Children with diarrhoea should be treated with ORS without loss of time.

The solution of ORS should be kept covered and used within 20 hours. If need be, fresh ORS solution should be prepared after 20 hours. Adults and older children should drink as much as they like from a cup or tumbler of ORS. A child under two years of age should be given half to one cup of ORS solution after each stool to compensate the loss of water and salts. Older children and adults should drink at least one to two cups after each stool. Easily digestible solid food such as boiled rice, soups, porridge, banana shake, curd, eggs, fish and well cooked meat are allowed even during diarrhoea. Treatment in hospitals and health centers depends on the degree of dehydration and other complications like fever and shock.

Cholera: Prevention is better than cure

Cholera is a diarrhoeal disease caused by the bacteria known as Vibrio cholerae. The infection leads to a form of diarrhoea in which the patient passes the so called rice-water stool instead of the usual formed faeces. The cause of such stools is now well understood. On entering the human intestine through contaminated food or water, the Vibrio cholerae lodges itself in small intestine. Here it secretes certain proteinaceous substances (known as enterotoxins), which attach to the specific receptors (Gm ganglioside)on the intestinal cell surface. A part of enterotoxin then enters the intestinal epithelial cells and activates the metabolic pathway in them leading to a profuse outpouring of fluids from them into the intestinal lumen. The bacteria themselves, however, do not invade the tissue. The disease had been endemic in India down the centuries, mainly in the Ganges and Brahmputra deltas in Bengal. The record of spread of Cholera throughout the world is available only after 1817 when the first pandemic occurred.  Since then six such pandemics are on record showing that the disease affected millions of people all over the world with high rate of mortality and morbidity. The seventh pandemic spread from the Sulwesi Island in Indonesia in 1961 that was caused by a biotype el Tor of Vibrio cholerae.

The man is the only source of the disease. The spread occurs through a contaminated environment. An infected patient excretes around 10⁷ to 10² bacteria per ml of stool which may further contaminate drinking water through sewage pollution. Wells and reservoirs of surface water (lakes and ponds) can get contaminated easily.  Food is another source of infection. All people in the endemic area should use boiled cooled water for drinking. Food handlers can also act as transmitters of infection. Flies act as mechanical transmitters of Cholera infection. Sanitation staff should be alerted to decontaminate the water-bodies with permitted chemicals.

The clinical picture may range from an asymptomatic carrier state to the fulminant disease. The most characteristic feature is rice-water stool and a precipitate vomiting. Dehydration may develop due to fluid loss and if not treated, the patient may collapse within 24 hours. Tentative diagnosis of disease can be made by the microscopic examination of stool, where a hanging drop preparation on a slide would show darting mobility of the bacteria. The specific diagnosis is made by growing the bacteria on artificial media in the laboratory and by serotyping of bacterial colonies grown on media.

The disease is treated by replacing the lost fluids and electrolytes, intravenously if the patient is admitted to a hospital or orally through oral rehydration powder. Tetracycline is the drug of choice. Sulphonamides, furazolidne and cotrimethoxazole have also been found to be useful. Drugs should never be taken without medical consultation. Cholera is one of the diseases which can be prevented by vaccination controlled by sanitation. The source of infection being man alone and the commonest vehicle of transmission is the water. Special attention should therefore be paid to the purity of water and the ice made from it for human consumption. The disposal of human excreta and garbage should be safe and soiled clothes of the patient must be disinfected. The isolation and treatment of Cholera patients is must. The outbreak of cholera should be notified at national level immediately for adequate prophylactic vaccination of people traveling to that area. The cholera vaccine (vaccine developed from attenuated Vibrio cholerae) is given by intramuscular injection provides effective protection for two to three months in around 89% of vaccinated population. However, oral vaccines of cholera are also available with variable protective efficacy.

Amoebiasis: Bowel amoebiasis and spread of infection to liver and lungs

The organism that causes amoebiasis is a unicellular parasite called Entamoeba histolytica. A variety of clinical presentations are seen. Though the disease is not a major health problem but in serious forms of amoebiasis, significant morbidity and mortality is unavoidable. We may have asymptomatic carriers of amoebic infection. On the other hand Entamoeba histolytica infection may result in fulminant dysentery with fever, diarrhoea, bleeding and even perforation of intestine. The organism can be identified in wet slide preparation of stool specimen obtained from infected patient.

The infection is transmitted by the faeco-oral route. The infection can be an asymptomatic one, that is, the victim could be in good health in-spite of harboring the Entamoeba histolytica infection. In severe cases of infection, Entamoeba histolytica can result in full-fledged frank dysentery along with colonic ulceration. Uncommonly, Entamoeba histolytica can invade organs other than large intestine. Liver is the second common site followed by lungs. The brain, genitals and the skin are other possible sites if infection by the amoeba. The majority of patients do not develop frank-dysentery, i.e. they do not develop diarrhoea with blood or mucus. Vague symptoms, such as discomfort in the tummy, irregularity of bowels, constipation, diarrhoea, griping and tenesmus occur in various combinations. In some cases, low grade fever, loss of weight, pallor, generalized non-specific aches and pains are common. The patient usually carries on his day-to day duties with sub-optimum health and efficiency.

The diagnosis of asymptomatic bowel amoebic infection can be established through repeated fresh stool microscopic examination. The sigmoidoscopic examination of ulcerative lesions of colon and microscopic examination of direct smears obtained from the ulcers would further confirm the diagnosis of amoebic ulcers. Invasion of liver by Entamoeba histolytica is the second commonest form of amoebiasis. The onset is usually insidious but an exceptionally rapid course can be seen during endemics of bowel amoebiasis. The presenting symptoms of liver amoebiasis are pain in the upper right quadrant of tummy, or fever or both. The presence of jaundice is very rare in patients with liver amoebiasis. Fever of uncertain origin is a common problem in many developing countries. One of the causes of the fever of uncertain origin could be amoebic infection of the liver.

The diagnosis of amoebic infection of the lungs and brain requires a high degree of expertise on the part of physician/clinician. The amoebic infection of brain is usually diagnosed at the operation table. Amoebic ulceration of skin is not very rare. Sophisticated techniques like serology and radio-isotopic scan can be of great help in establishing the diagnosis of amoebic abscess of liver, lung or brain. The treatment of amoebiasis is highly effective once a correct diagnosis has been made. Eradication or prevention of amoebiasis in any locality can be achieved only if there are optimum ways of sewage disposal and personal hygiene.